Heat and dry to continue says BoM Climate Outlook
Thu 28 Nov 2019
The BoM issued its main monthly Climate Outlook today giving a high likelihood that warmer and drier than average conditions will continue through summer for almost all of the continent. The exception is that better than average rain is expected in NW WA from January, with this improvement slowly spreading east through to the end of the outlook period in March. However, apart from keeping daytime temperatures down in NW WA from January, the effect on both maximum and minimum temperatures is expected to be minimal, with over 80% probability of them being above average at least to the end of February.
The main driver of these conditions continues to be one of the strongest positive Indian Ocean Dipole events (IOD) since accurate records began in the early 1960s. It is caused by an anomaly in sea surface temperatures across the Indian Ocean: 1 to 2° below normal in the east near Australia and 1 to 2° above in the west near Africa. The cooler waters are producing our lack of rain while warmer waters have given large parts of eastern and central Africa disastrous flooding for months. Added to cooler SSTs in the Indian Ocean are cooler than normal SSTs to our east in the Coral and Tasman Seas and to our south in the Southern Ocean, so wherever the air comes from it will bring below average moisture.
The IOD normally begins to break down during December, but this year that breakdown is expected to be well into January. The strongly positive IOD will also influence the arrival of the Australian monsoon. The monsoon trough has been exceptionally late in leaving India this year; its normal arrival in Darwin is the last week of December, but this year it is not expected until well into January.
The second climatic factor that has been exacerbating fires and drought across southern Australia has been the continuing strongly negative Southern Annular Mode (SAM). Frontal systems have been pushing farther north than normal, but with a lack of moisture have only produced strong, drying NW to SW winds and duststorms, intensifying the danger of bushfires.
New regional climate guides designed for farmers
Thu 28 Nov 2019
The BoM and CSIRO have produced a set of 56 Regional Weather and Climate Guides produced specifically for farmers and mostly based on Australia's Natural Resource Management Districts. There is a strong focus on each region's climate risk, especially the changes that have occurred in recent years.
They have had considerable local input. The detailed FAQ says they have "been informed through interviews with local producers, agricultural advisers, local government, and other relevant stakeholders from the 56 NRM regions in Australia. Importantly this involved visiting the regions and gaining insights into what is relevant, and what's not, with regard to weather information used to inform agricultural decisions."
After a summary of significant changes in weather and climate in the last 30 years and a thumbnail sketch of the region's agriculture, there are sections that cover annual rainfall, rain reliability and timing, and temperature. Depending on region there may be sections on evaporation, frost, wet season timing, timing of autumn and spring breaks, evaporation and frequency of useful rain events. Each region covers the weather and climate issues that are specific to it so there is some variation, but all deal in detail with the impacts of climate change that have been occurring in the past 30 years.
If you haven't discovered these guides yet, visit the one for your area now.
For information on annotations (*, †, ‡, etc), translation using your browser, abbreviations and how AWN attributes sources go here.